Mercury type relay



Se t. 26, 1950 H. c. HARRISON 2,523,366

MERCURY TYPE RELAY Filed Sept. 28, 1946 2 Sheets-Sheot 1 3 7 PZIT/A UM IN VE N TOR H. QHARR/S N A TTORNE Y fi 1950 c. HARRISON 2,523,366

MERCURY TYPE RELAY Filed Sept. 2a, 1946 2 Shet-Sheet 2 /36 F IG. 9

A T TORNEV Patented Sept. 26, 1950 MERCURY TYPE RELAY Henry C. Harrison, Port Washington, N. Y., al-

signor to Bell Telephone Laboratories, Incorporated, NewYork, N. Y., a corporation of New York Application September 28, 1946, Serial No. 700,138

6 Claims. (01. 200-112) This invention pertains to electromagnetic relays and more particularly to such relays in which a conducting fluid and cooperating electromagnetically-controlled elements are ar ranged to provide contacts which may be made slow to operate, slow to release, fast to operate or fast to release as well as to provide various combinations of contact operate andv release times, to meet the requirements of switches and relays employed in electrical circuits, particularly in communication switching circuits. There are known in the present art a number of devices which delay the operation and/or release of a relay or to provide various combinations of contact operate and release times. However, when'a considerable delay interval in operating or releasing a relay is required, it is frequently necessary either to supplement the relay with a timing circuit, such as a condenser timing circult, or to employ a relatively elaborate and expensive switch including a mechanical relay. There is no basic relay available today which will provide a wide variation of make and break delay intervals without the use of such auxiliary devices as mentioned hereinbefore.

An object of the present invention is the provision of relay structures which will fulflll the needs set forth in the foregoing discussion.

A more particular object of this invention is the improvement of relays which include a delay feature.

Another object of this invention is the provision of a compact inexpensive relay or switch having a basic structure which can be arranged to provide various combinations of contact operate and release intervals and which structure can be readily adapted to change the contact operate and/or release delay intervals over a very wide range.

Another object of the invention is to provide a relay having fluid contact elements and including a delay feature which relay can be mounted on vertical mounting plates with the longitudinal axis of the relay in a horizontal plane.

The invention may be understood from the following description when read with reference to the associated drawings which disclose a preferred embodiment of the basic relay structure of the invention and a number of preferred embodiments of interchangeable. fluid contact assembly units arranged to provide various combinations of contact operate and contact release intervals. The invention is not however limited to the described and illustrated embodiments but may be practiced when incorporated in many other forms suggested by the following description and drawings. In the drawings:

Fig. 1 is a left elevation, and Fig. 2 is a front elevation, both partly in section, of the fluid contact assembly unit of the relay in which the contacts are arranged to provide a relatively long delay on closure and a relatively fast break;

Fig. 3 is a left elevation and Fig. 4 is a front elevation, both partly in section, of a second embodiment of the fluid contact assembly unit of the relay. showing a unit having contacts arranged for a relatively short delay on closure and a relatively long delay on break;

Fig. 5 is a left elevation and Fig. 6 is a front elevation, both partly in section, of a third embodiment of the fluid contact assembly unit of the relay, showing a contact unit having a relatively long delay on both contact closure and contact break;

Fig. 7 is a left elevation and Fig. 8 is a front elevation, both partly in section, of a fourth embodiment of the fluid contact assembly unit of the relay, showing a contact unit having a relatively long delay on contact closure and a relatively short delay on contact break;

Fig; 9 is a plan view partly in section, Fig. 10 is a vertical section on the line Hl|ll in Fig. 9, and Fig. ll-is a right-hand end view taken in the direction of the arrows Hl| in Fig. 9, of a preferred relay assembly of which any of the relay contact units of Figs. 1 to 8 form a part and in which relay the contact units may be interchangeably mounted.

Before proceeding with the detailed description of the relay assembly the various contact unit assemblies will be described.

Refer to Figs. 1 and 2 which show a fluid contact assembly unit having a relatively long delay on contact closure and a relatively fast break.

In Figs. 1 and 2, an impervious generally cylindrical container i, which may for instance be of non-magnetic material such as glass or plastic but preferably is of stainless steel, has a lefthand end which may be hemispherical and a right-hand end terminated in an outwardly pro- Jecting annular flange 2. Sealed to the flange 2 is the flange 3 of a stainless steel tubular eyelet I, well known in the art, sealed in the right-hand end of which is a glass bead. Welded to the flange 3 at any part thereof is a conductor l I. Projecting through the glass head 5 into the interior of the container is a conductor 6. A flat spring steel strip support 1 projects at its right-hand end into the glass bead 5 and is secured therein.

amazes The left-hand end of support 1 is bent first downwardly and then to the left slightly, at right angles, where it is welded to the right-hand end of armature scoop 8 which is preferably formed of a unitary piece of magnetic alloy material. The left-hand end of armature scoop l and its front and rear side walls, as seen in Fig. 2, are formed upwardly. There is no well at the righthand end of the armature scoop. The righthand portions of the side walls 9 may be tapered downwardly toward the bottom of the scoop. Sealed between the front and rear side walls of the scoop 8, near the top of each wall, is a glass bead I through an aperture in which the lefthand end of conductor 8 extends and in which the conductor I is sealed. A short distance to the left of glass bead III, conductor 8 is bent downwardly at an angle. The left-hand end of conductor 6 may be plated with platinum which wets with mercury. Sealed in the upper portion of glass bead i0 and projecting upwardly therefrom is a short hard-rubber insulator l2 which abuts against the inner top surface of the container I and serves as a stop for the armature. The lower portion of the chamber formed by the container i and the eyelet 4 is fllled to about Vs its depth with a conducting fluid II, such as mercury or mercury combined with other materials, well known in the art, to improve its characteristics as a contacting material.

The lower level of the armature scoop 8 is normally above the upper surface of the conducting fluid, so that the circuit, one side of which extends from the conductor ll through the flange I and the eyelet 4 to the fluid l3, and the other side of which extends through conductor is open. when the relay coil, such as the coil ll in Fig. 9 is energized, as will be described indetail hereinafter, the left-hand end of armature scoop I and the left-hand end of conductor 6 are drawn downwardly as a unit against the tension of supporting spring 1 into the fluid l3 to such a depth that the fluid overflows the side walls at the left-hand end of the scoop. After the fluid has risen sui'flciently in the interior of the scoop, the left-hand end of conductor 8 makes contact with the fluid and the circuit is closed. When the magnetic coil such as coil I4 is no longer energized the scoop armature 8 is snapped upwardly by spring I into its normal position in which its bottom slopes downwardly toward the right and the mercury is spilled rapidly out of the open right-hand end Y of the scoop.

The arrangement per Figs. 1 and 2 provides a delay in contact closure but a delay which can be made relatively short, if desired, by controlling the dimensions of the scoop, the height of the fluid and the position of the contacting end of conductor 6 with relation to the bottom of the scoop.

Refer now to Figs. 3 and 4.

The arrangement per Figs. 3 and 4 differs from the arrangement per Figs. 1 and 2 in that instead of a scoop armature having an open rear end the rear end of the armature it is closed with a vertical wall 20 and a small circular aperture 2i in a thin platinum disc 33, welded to the inner surface of the bottom of the armature, is in axial alignment with a slightly larger aperture 34 in the bottom of the armature, through which apertures 34 and 2i the fluid, such as mercury, flows to enter the interior of the armature. Platinum wets with mercury but dissolves thereby to only a negligible amount. The thickness of the platinum disc II is less than and preferably much smaller than the radius of the circular aperture 2| so as to prevent variations in the flow of fluid tm'ough aperture 1| due to temperature changes. Investigation by applicant has disclosed that with the aperture 2| so proportioned; the rate of flow is less dependent on changes in viscosity which varies with temperature. The left-hand end of the conductor Il may be bent downwardly or may be horiaontal as shown depending upon the delay interval to be obtained.

A-coiled spring II is formed in' the conductor 24 intermediate the armature and the glass bead 2|. Welded to the lower right-hand end of the armature is a l-shaped element 21 formed of a flat spring steel strip. The conductor 2. projects through the glass head It into the chamber. It is bent downwardly as at II and then horizontally to the left as at II and then forwardly at right angles as at II where it abuts the lower angle of the Z-shaped element TI and forms a pivot contact about which the Z-shaped element and the armature ll may rotate.

As the armature II is drawn downwardly a small amount of conducting fluid flows through the aperture 2| into the interior of the armature, however the downward movement of the armature under the influence of the magnetizing coil is made quite fast so that the conducting fluid quickly overflows the armature walls and rises in the armature to make contact and close a circuit through contact 22. when the magnetizing coil is deenergized the armature I! is snapped upwardly and the conducting fluid drains slowly through brushing 2|. It is particularly pointed out that since the circuit is to remain closed for an interval after the magnetizing coil is deepergized. the level'of the fluid must be such that it makes contact with the bottom surface of the armature when the armature is raised with its load of conducting fluid.

Both the operate and release times may be varied by varying the position of the contact 22 with respect to the interior bottom surface of the armature as well as by varying the capacity 01 the armature, the size of aperture 2|, the magnetizing force. the tension of the spring 25, the quantity of fluid in the container and the capacity of the container. When all other motors are nxed a considerable variation in release time may be obtained by varying the position of contact 22 with respect to the bottom of the armature.

The arrangement per Figs. 5. and 6 resembles the arrangement per Figs. 3 and 4.

The armature is supported on a thin fiat strip ll of conducting material to which the armature is welded. The conductor 41 may be apertured in axial alignment with the aperture in the bottom of the armature. The armature 40 is arranged with relatively high walls so that the fluid does not overflow the walls when the armature is drawn downwardly. The conducting nuid flows into the interior of the armature and out of the armature through an aperture in the bottom of the armature arranged as described for Figs. 3

and 4. Such an arrangement provides arelatively long delay both on contact closure and contact break. The eyelet is arranged in a slightly different manner than in Figs. 1 and 2 or Figs. 3 and 4, being equipped with a flange 4d of much larger diameter. The periphery of the flange is trimmed to conform to the periphery of the flange of the container 48. By providing eyelets having flanges otwidediameterandtiimmingtheflangesto amazes conform as required an eyelet of a single standard size may serve containers of varying sizes.

In the arrangement per Figs. 7 and 8 the armature 40 is a rectangular box-like structure having an extended bottom member 40, side walls which are tapered near their right-hand ends such as at BI, and an open right-hand end 33. The armature 48 is supported by and is rotatable about a transverse steel rod 50 welded to the bottom of the armature. As seen in Fig. 7, the opposed ends of rod 00 project into opposed cavities in hollow ears 82 and 54 forming protuberances on the surface of container 56. A cylindrical ceramic insulating bushing 50 extends between the side walls of the armature. The bushing is reinforced by an axial steel rod 60 the opposed ends of which project into opposed apertures 62 and 04 in the front and rear side walls of the armature. The bushing is fixed in position Just to the right of the shortened top member of the armature and to the left of the rod 50. A conductor 60 projects from the exterior through the glass bead 81 in the eyelet into the interior of the chamber. A coiled spring portion 60 is formed in the conductor 66. The conductor terminates in a contact element I0, the right-hand end of which abuts against and is depressed downwardly by the lower surface of the ceramic bushing 50. The spring thus tends to rotate the armature 40 counterclockwise about rod 50 as a center. Sealed in the bottom 49 shortly to the left of rod 50 is a combination entrance and exit port 72, which may for instance be a hollow cylindrical cup opening into the bottom 43 and secured thereto by a flange I4 sealed to the bottom 49. A circular aperture 16 is formed in the bottom of the IpOlt I2, and a thin circular disc of platinum 80 having an orifice 82 in axial alignment with aperture II is secured to the bottom of the port.

When the left-hand end of the armature 48 and the contact I0 are drawn downwardly under the influenceof the magnetizing coil, the conducting fluid flows slowly through the orifice 82 and the aperture 16 into the interior of the port 12 and rises into the interior of the armature, engaging contact I0 and closing a circuit between conductor 04, welded to the exterior surface of the eyelet jacket 86, and conductor 66. When the magnetizing coil is deenergized, the armature 40 is snapped upwardly by the spring 68 and the conducting fluid is emptied almost instantly out of the armature. This arrangement provides a relatively long delay interval on contact closure and a quick contact break.

Refer now to Figs. 9, 10 and 11 which disclose a preferred relay structure in which the various fiuid contacting units of Figs. 1 to 8 may be interchangeably mounted. It is particularly pointed out, however, that the contacting units are not limited to incorporation in such a relay structure as is shown in Figs. 9, 10 and 11 but may be employed with many other relay structures which will readily suggest themselves to those skilled in the art.

The relay structure per Figs. 9, 10 and 11 comprises a number of major component elements namely, an energizing coil assembly I4, 9. combination magnet element and mounting bracket 90, a magnetic path closure element and support 32 for the contact unit assembly and the contact unit assembly 94 which may be any of the contact unit assemblies per Figs. 1 to 8 or adaptations of those per Figs. 1 to 8 to provide required combinations of delay on contact closure or break.

The energizing coil I4 may be wound on an independent spool of insulating material separable from the magnetic core 03. The spool has an axial opening generally conforming in section to the section of core 00 so that it fits snugly about the core. The magnetic element 30 is a flat, generally rectangular, plate of magnetic material bent upwardly at its left-hand end to form a mounting bracket which is perforated and tapped I00 and I02 to accommodate mounting screws and perforated and bushed with insulating material I06, I08, H0, and H2, to accommodate the conductors H4 and H0, which connect to the terminals of the coil I4 and to the conductors I20 and I22 which connect to the contact unit. The horizontal portion of the magnetic element 00 is separated by longitudinal notches I24 and I20 into three legs. The middle leg 00 which forms the magnet core is shorter than the two outer legs I30 and I32 being cut oil at right angles at I28. The outer legs are interconnected by a transverse plate 92 of magnetic material which forms a closure for the magnetic paths. The under surface of plate 92 may abut the upp r surfaces of legs I30 and I32 near the right-hand extremities of the legs and the element 82 may be secured to the legs I30 and I33 by means of screws Ill and I33. The middle portion I34 of element 02 may be concave slightly as seen from above to conform to the outer surface ofv the eyelet of the contact unit assembly to provide a bearing surface for the eyelet portion of the contact assembly. The contact unit assembly is supported at its left end by the right-hand end of the pole-piece. Both the right-hand end of the pole-piece and the concave portion I34 of element 02 may be apertured to receive spring wire pro- Jections 31 and 33 which may be flexed each toward the other momentarily while the projections are being inserted in the apertures and then released to secure the contact unit in position.

- It is particularly pointed out that the space between the right-hand end of the pole-piece 30 and the left-hand end of the concave portion I34 of element 92, constitutes a magnetic gap which is bridged by the armature in the contact assembly unit. When the coil I4 is deenergized the armature is in its upper position. When th coil is energized the left-hand end of the armature is drawn downwardly to narrow the magnetic gap. The magnetic flux may be considered to flow from the core 96 toward the rear where it divides. One-halt fiows toward each outer leg, then forwardly through'outer legs I30 and I32, then from each leg inwardly through element 82 toward the center of element 02, then across the right-hand gap to the right-hand end of the armature, such as armature 0 in Fig. 1, then through the armature and across the left-hand gap between the armature and the pole-piece 96 to the pole-piece.

It is pointed out that the magnetizing coil and the contact unit assembly are arranged as separable units to facilitate the assembling of relays having various coils and contact units to meet specific requirements. The element 92 is made separable to facilitate the mounting of the coil on the core 06. It is also pointed out that the contact unit may be mounted in any other convenient manner such as by means of spring-type clamps or clips secured to the pole-piece 9'6 and to cross element 92. Although the legs I 30 and I32 are shown in the Figs. 9, l0 and 11 as'being arranged with their broad opposed surfaces horizontal, the legs may be formed upwardly so that the broad surfaces are in a vertical plane and the cross element 02 modified to conform, to provide asaases a more compact relay when a saving in mounting space is desirable.

The relay is mounted by screws ill and I" which pass through apertures in the vertical mounting plate I30 and in the insulator I to engage in tapped holes in the vertical bracket element 00, to support the relay so that the longitudinal axis of the coil and of the contact assembly unit is horizontal. Asthus arranged the relay may be mounted in the same manner as relays are mounted generally in the communication switching plant without the necessity for making special provision therefor.

What is claimed is:

A 1. An electromagnetic relay, comprising a scoop shaped armature, said armature having a walled portion and an unwalled portion, a pool oi'conducting fluid, means comprising a magnetizing coil for actuating said armature so that said fluid overflows said walled portion to enter the interior of said scoop and establish an electrical contact at a flrst time, and means for tipping said scoop to permit said fluid to flow out through said unwalled portion to break said contact at a second time.

2. An electromagnetic relay arranged for providing a relatively fast contact make and a relatively slow contact break, comprising a hollow armature having a large opening at the top and an oriflce in the bottom, a pool of conducting fluid, means comprising a magnetizing coil for.

drawing said armature down into said pool so that said fluid flows through said large opening into the interior of said hollow armature to establish an electrical contact, and means for withdrawing said armature from said pool to permit flow of said fluid into the interior or said armature for establishing an electrical contact, and means for releasing said armature to permit said fluid to drain through said oriflce to open said contact.

4. An electrical relay arranged for a slow contact closure and a fast contact opening, a hollow armature in said relay, an oriflce in said armature, a large opening in said armature, a pool of conducting fluid, means comprising a magnetizing coil for displacing said armature with respect to said pool, so as to permit said fluid to flow core, said coil readilyseparable from said core, i magnetizable strip interconnecting said legs,

ahd a liquid contact assembly unit, arranged ior a particular contact operate and contact release delay-- combination, said unit including a magnetizable armature, and a conducting liquid both in an impervious container, mountable in a gap between said strip and said core, said unit interchangeable with other units to provide other delay combinations.

6. An electric relay comprising a container, a contact in said container connected to a conductor extending through the walls thereof insulatedly with respect to a fluid hereinaiter mentioned, a vessel in said container empty or said fluid in the non-conductive position of said contact, said vessel being generally concave on its upper side, conductive fluid in said container, said vessel being generally magnetic, means operable magnetically to lower said contact and vemel sufliciently with respect to the surface or said fluid to cause it to become sufliciently fllled with said fluid to conductively contact said fluid and thus temporarily establish a circuit between said conductor and another conductor through said fluid, and means to restore said vessel to its unlowered position and open said circuit.

HENRY C. HARRISON.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS Germany Dec. 3, 1040 

